Perhaps you should try some spelling variations:
cong ngang » cong nhan, cong quang, cong lang
truong va » truong dai, truong cao, truong dao
dung cong » dung trong
hoc hieu » hoc thieu, hoc hien, doc hieu
tuong va » thuong va, luong va, duong va
toan tai » toan tap, doanh tai, toan cao
toan ban » van ban
hieu va » lieu va, hieu qua

You may be able to get more results by adjusting your search query.

• If you are trying to use Boolean operators, they must be ALL CAPS: hoc hieu va - manh ((tuong va) OR (truong va)) dung cong ngang ((toan tai) OR (toan ban))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc hieu va - manh ((tuong va) OR (truong va)) dung cong ngang ((toan tai) or (toan ban))~".
• Adding a wildcard symbol may retrieve word variants: hoc hieu va - manh ((tuong va) OR (truong va)) dung cong ngang ((toan tai) or (toan ban))*.